battery plus and negative not quite black and white:
You never know who wired it up and the standard colors are red + and black - to the best of my limited knowlege of trailers; ours is white + and black - but not sure could be white -. We are now running battery with no outside power or water available other than a hand pump well at trailer location and need the battery.

Research reveals that the majority of the folks who claim some experience with trailer battery wiring think WHITE = positive. Most of the rest of us suffer from a familiarity with the colors of leads from vehicle starting batteries. The insulation color of the conductor that's fused in the DC distribution panel WAS, IS, AND EVER SHALL BE the insulation color of the conductor connected to the POSITIVE battery terminal. What color a DC conductor SHOULD BE is open to free and not often enlightened interpretation.

White wire is the ground (-) wire in the camper to tow vehicle connection.
Other than that, Jack The Rabbit is correct. It seams anyone running dc wire simply uses whatever they may have at hand.

RED and GREEN felt disks are sold at battery supply counters to be placed on the + and - terminals of the battery to prevent corrosion. The red should be placed on the + terminal.

Your tow vehicle will have Red connected to the + and a black wire connected to the frame. Then: The actual receptacle for the trailer has a White wire for the - and it could also be connected to the frame.

It's easy to see why this might get complicated for such a simple subject.

As a new Scamp owner, it took me a while, but with help from my hub, I got the wires all sorted out and figured out what was pos and what was neg. Then I realized the battery with the trailer I bought was DOA. So I'm shopping for a new battery. Does anyone know what the largest size you can use. I don't want to change to 2 batteries to keep my tongue weight down, but thought the larger battery would give me some more amps when dry camping. I saw a Group 31 deep cycle battery and thought this would be a good possibility. I'm also going to be getting a portable 90 watt solar system. THANK YOU.

The size and wgt. of the battery goes up with the no. A group 27 is physcially larger and heavier than a 24; a 31 than a 27. So a bigger battery adds some wgt. and a group 31 is a healthy proposition wgtwise. I don't recall the increase in wgt. off hand; there are a lot of charts with specs on the web. You could cf. wgt of a single 31 against a pair of 24s. You might also want to read up on "equallization" of charge on multiple batteries which could possibly push you further in the direction of a single batt.

Thanks Jack. I looked up the specs and 2-24s are much heavier than 1-31. So I will go that route with a single battery, unless there's a reason the 31 would not be compatible with the wiring in the Scamp. Any discussion of electrical and my eyes start to glaze over so any input is appreciated.
Thanks,
Linda